The invention relates to a ski having a top chord, a bottom chord and a core arranged between them, varying in height over the length of the ski and divided by at least one intermediate chord extending from the toe portion or shovel approximately to the end of the ski.
Known skis which have a so-called sandwich construction consist in cross-section of the following structural elements:
A first layer called the top chord consisting of a stiff or resistant material, for example aluminum or a glass-fiber-reinforced plastic or a combination of these materials, which layer is coated for optical reasons on the top thereof, which forms the upper surface of the ski;
another layer called the bottom chord likewise consisting of a stiff or resistant material, for example of the above-mentioned kinds;
an intermediate layer between the top chord and the bottom chord and called the core, this intermediate layer consisting, for example, of wood, aluminum honeycombs, glass-fiber-reinforced plastic or foamed plastic, and
a running sole, for example of polyethylene, which is protected laterally by steel edges.
Vibrations are caused in the ski, in particular through shocks or impacts acting on its toe portion, and are propagated in its longitudinal direction, whereby its running properties are impaired. In order to keep these vibrations as small as possible, it is known to design the ski so that it extensively damps such vibrations.
This has been achieved heretofore by making the top and bottom chords particularly thick, making the core thick, providing rubber inserts in the core or providing rubber inserts between the chords and the core. These expedients may be provided separately or in combination. Thick dimensions for the chords or the core are disadvantageous, however, inasmuch as the ski is thereby given damping properties over its entire length, although this not desirable for its terminal zones.
Damping properties are obtained only in the middle zone of the ski by giving it an increased thickness in its middle zone. This, however, is again disadvantageous because in this way the ski becomes inflexible in the middle zone.
It is furthermore known from French Pat. 2,048,079 to provide between the top chord and the bottom chord an intermediate chord extending in the neutral zone of the ski, by which the properties of stiffness of the ski are improved.
As against this, the object of the present invention is to provide a ski having at least one intermediate chord so that it exhibits improved damping properties against longitudinal vibrations. According to the invention, this is achieved in that the at least one intermediate chord extends in the zones of the toe and heel portions of the ski so that it closely follows the top chord and extends in the middle zone of the ski at a distance from the top chord varying over the length of this zone and at a distance from the bottom chord remaining constant over the length of the said zone.
The core part closely following the top chord is preferably made of harder material than the rest of the core. The at least one intermediate chord may be made of aluminum or glass-fiber-reinforced plastic.